Bearing



May 1, 1934.

c. R. SHORT 1,957,111

Original Filed Sept. 22, 1927 JLILIL gwuentoz Patented May 1, 1934 NITEDSTATES BEARING Charles lit. Short Clermont, Fla, assignor, by mesneassignments, to General Motors Corporation, Detroit, Mich., ware acorporation of Dela- Driginal application September 22, 1927, Serial No.221,340, now Patent No. 1,819,272, dated- August 18, 1931. Divided andthis application. @ctober 8, 1930, Serial ,No. 487,138

2 Claims.

This invention relates to machine elements having surfaces adapted to beplaced in rubbing contact with a relatively'movable part, such as abearing for a shaft.

It has been heretofore found desirable to employ porous metallicmaterial as a bearing surface in elements of this character, and tosecure this porous metallic material to a backing or reinforcing memberof denser metal, by means of a metallic bond between the porous anddenser members, said bond alloying with the porous and denser metals tosecurely attach said metals together. Under certain conditions as, forinstance, when the machine element becomes highly heated, the bond maybe wholly or partially broken down due to a tendency of the porousmaterial to absorb the bonding material when hot, thus permitting theporous bearing surface to become loose. It is the primary object of thisinvention to provide a novel and improved machine element of thischaracter in which the porous metallic bearing surface is securelyattached to the reinforcing member in such a way that it will remain soattached during all conditions of manufacture and operation.

It is also a further object of this invention to devise a novel methodof making machine eleq ments of the type described in which the bearingsurface is attached to the reinforcing memher in an improved manner.

With these objects in view, one feature of the invention consists in theprovision of a machine element having a porous metallic bearing surface,secured directly to a denser metal reinforcing member, without the useof any intermediate bonding material.

A further feature of the invention consists in a method of making such amachine element in which the step of attaching the porous bearingsurface to the denser metal back consists in heat ing the two metalelements to a high tempera-1 ture while clamped together under pressure.The invention also contemplates the heating of the elements clampedtogether as described in a liquid bath.

This application is a division of Serial Number 221,340 filed September22, 1927, Patent No. 1,819,272 ssued August 18, 1931;

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing, wherein a preferred embodiment of one form of the presentinvention is clearly shown.

In the drawing:

Fig. 1 is a plan view of a preferred form of porous metallic plate.

Fig. 2 is an enlarged sectional view on the line 2-2 of Fig. 1.

Fig. 3 is a sectional view, largely diagrammatic, of apparatus used toweld the porous metallic plate to a reinforcing member, for example aconnecting rod.

Fig. 4 is an enlarged fragmentary section of a connecting rod bearingformed according to this invention.

In my prior Patent No. 1,768,529, issued June 24, 1930 and my Patent No.1,834,746 issued December 1, 1931, I have disclosed bearings having afacing consisting of a thin sheet of porous metallic material, securedto a reinforcing backing of denser metal having a greater tensilestrength, andcertain methods of making such bearings. The porousmetallic element employed in such bearings has been either such anelement as described in the patent to H. M. Williams et a1. Number1,642,347, issued September 13, 1927, or such an element as described inmy above mentioned Patent No. 1,834,746. The porous metallic elementdescribed in the Williams patent is of substantially the same porositythroughout, while that disclosed in my Patent No. 1,834,746 is oflaminated construction having layers which differ in degree of porosity.The methods employed to make these metallic elements form no part ofthis invention and need not be described in detail herein. Briefly, itmay be said that the metallic element disclosed in the Williams patentis made by briquetting a mixture of metal powders, a filler such asgraphite, and a volatile void forming substance such as salicylic acidand sintering the briquette at proper temperature. The

metal element disclosed in my Patent N 0. 1,834,746

is made by adding a layer, principally copper or copper alloy to theporous metallic-element disclosed in the Williams patent.

In Fig. 1 of the drawing, is disclosed a metallic element 20 which is ofnovel and improved form to give the best results when bonded directly toof copper.

the reinforcing member without use of an intermediate metal bond such astin, which has been formerly employed in making bearings with a porousmetallic facing. It has been found that when the porous metallic facingis secured directly to the denser metal backing, particularly byelectrically welding as set forth hereinafter, better results areobtained if a portion only of the two contacting surfaces are bonded.The metal element 20 according to the present invention is formed withan embossed surface, having areas 21 projecting above the remainingsurface of said metallic element. The element is embossed in anysuitable manner, for example, by pressing with a die of proper shape tosecure the desired formation. It will be understood also that the raisedareas 21 may be formed from the body of the metallic element as theelement itself is formed, or may be formed thereon at a subsequentoperation. The projecting areas 21 are joined to a reinforcing member ofa denser metal in the manufacture of a bearing as later described.

The metallic element described may be of substantially the same degreeof porosity throughout or may be an element having the laminatedconstruction described in my above mentioned patent No. 1,834,746. It ismore desirable to use the laminated form of metallic element and formthe projecting areas 21 on the less porous metallic layer, for thereason that the less porous layer has greater tensile strength than themore porous metallic layer, and when attached to the denser metalreinforcing member, a stronger bond is formed which will require agreater force to break it down, than if the more porous material weresecured to the reinforcing member. As set forth previously and morefully explained later, a more desirable bond is secured when a metalelement having an embossed surface is secured directly to itsreinforcing back by welding or heating to high temperatures, but it willbe understood that these, methods of bonding are not limited to the useof the embossed element, and may be employed to attach two planesurfaces together also.

This invention contemplates the bonding of the element 20 to a densermetal reinforcing member by the application of heat. To secure a bond inthis manner the element 20 and the reinforcing member are clampedtogether in any suitable manner under comparatively light pressure andare heated while so held to a temperature of 1525 to 1550 F. and arethen quickly cooled. This temperature will depend on the materials used.

The clamped assembly maybe heated in any desirable manner, andsatisfactory results have been obtained when said assembly is heated ina bath of molten salts. l

The porous material may be composed of copper and an alloy of copper andother substances. When the porous material is heated while held incontact with the denser metal backing to the temperature referred to, apart of this alloy of copper and other substances melts, but thespecified temperature is less than the melting point On cooling themelted portion of the alloy forms a bond attaching the porous metal toits reinforcing body.

It is also within the scope of this invention to effect the joinder of aporous metallic element to a denser metal member by heating to hightemperatures by means of an electric current to electrically weld thetwo elements together. In accordance with this method of bonding the twoelements, the porous element: is held against the member to which it isto be attached, with the projecting areas 21 in contact therewith. Oneconductor of an electric circuit is in electrical connection with thereinforcing member, while the other conductor of said circuit is inconnection with an electrode which is brought into engagement with theexposed surface of the porous element.

In Fig. 3 is disclosed diagrammatically a suitable apparatus foreffecting joinder of the two metallic elements by electric welding. Theapparatus disclosed is designed to weld a porous metallic element ofcurved form to the curved surface of a connecting rod bearing. Asdisclosed a connecting rod 22 is supported on a supporting cradle 23having a hole therein through which the rod extends. The cradle ispivoted at 24 so as to have a rocking movement. The porous element 20 isplaced in the curved end of the rod 22, with the projecting surfaces 21in contact with the surface of the conneoting rod. An electrode 25having a roller 26 adapted to engage the upper surface of the metallicelement 20 is supported above such element and is adapted to be broughtin o engagement therewith by any suitable means so as to press theelement 20 into engagement with the connecting rod with a moderatepressure. A conductor 27 constituting one branch of an electric circuitconnects the electrode with a suitable source of electrical energy,while a conductor 28 connects the cradle 23 with such source of energy,a switch 29 being provided to make and break the circuit as desired.

When the electrode is in such position as to hold the element 20 againstthe adjacent surface of the connecting rod the switch is closed and thecradle is rocked to bring the roller 26 above the projections 21successively. As the roller successively comes above the areas 21, apositive contact is established at such areas and they are welded to therod 23. By using a metallic element having raised surfaces a highertemperature is possible at the contacting surfaces with a given currentand a better weld is secured than if it be attempted to weld one' planeelement to another throughout their entire contacting areas.

While apparatus is shown for carrying out this method in the making ofcurved bearings only,

it is obvious that said method can be employed in the manufacture offlat bearings. In making such bearings, instead of using a pivotedcradle such as 23, a cradle having lateral movement with respect to theelectrode 25 could be employed.

In Fig. 4 is disclosed a connecting rod assembly having a facing ofporous material bonded to the steel rod. An element 20 is shown betweenthe rod 22 and the cooperating crank shaft 30.

In Fig. 4, which is on an enlarged scale, it will be seen that betweenthe projections '21 are channels 31 which are formed when saidprojections are formed on the element 20. These projections will serveas oil channels for any oil which comes in contact with the bearing,permitting any such 1 oil to reach a considerable part of the bearingsurface. Obviously such oil will be more readilyabsorbed than if theporous element 20 had a plane surface thereof secured to the reinforcingmember, so that any oil reaching the bearing would have to be absorbedby said element 20 through the ends thereof.

While the form of embodiment of the present invention as hereindisclosed, constitutes a preferred form, it is to be understood thatother forms es-2311 i might be adopted, all coming within the scope ofthe claims which follow. I

What is claimed is as follows:

1. A bearing comprising a relatively strong metal back and an oilimpregnated porous bronze bearing lining therefor, said lining having a.series of relatively small raised areas on its surface contacting withsaid metal back, said raised areas being welded directly to said back.

2. A bearing comprising a relatively strong

